An evaporator is an apparatus for increasing a temperature of the coolant condensed and liquidized by a condenser so as to evaporate the coolant and then discharging the evaporated coolant.
In order to improve a discharging temperature, in a four-tank type evaporator, the coolant is introduced to an upper tank and flowed to a lower tank through a tube and then flowed again to the upper tank through the tube so as to be discharged.
Particularly, in case of a laminated evaporator, an end-plate is disposed at both right and left sides of the evaporator. The end-plate is formed with an inlet manifold and an outlet manifold. The condensed and liquidized coolant is introduced through the inlet manifold, and the evaporated coolant heated during the ciculation in the evaporator is discharged through the outlet manifold.
In a conventional evaporator, as shown in FIGS. 1 and 2, an inlet end-plate 150 and an outlet end-plate 160 placed at both right and left sides thereof are arranged symmetrically, and an inlet manifold 151 and an outlet manifold 161 are coupled to upper sides thereof. Further, at each upstream side of the inlet end-plate 150 and the outlet end-plate 160, there are formed an inflow part 152 and an outflow part 162, respectively. Between the inlet end-plate 150 and the outlet end-plate 160, there is formed a tube 120 by coupling a tube plate 121. A plurality of tubes 120 are laminated in a row, and a tank 130 communicated with the tube 120 is formed at upper and lower sides of the tube 120, and a fin 140 is interposed between the tubes 120. In this situation, the tank 130 communicated with the tube 120 is connected with another tank 130 communicated with other adjacent tube 120 to be communicated with each other.
The inlet end-plate 150 and the outlet end-plate 160 are respectively formed with a communicating opening 153, 163 communicated with the tank 130.
FIG. 3 shows a flowing path of coolant in the conventional four-tank type evaporator.
The flowing path of coolant in the evaporator will be described. The liquidized coolant introduced through the inflow part 152 of the inlet end-plate 150 is flowed in the inlet manifold 151 and moved through the communicating opening 153 to the tank 130 positioned at the upper side of the tube 120 and then moved through a flowing path 122′, 122″ of coolant to the tank 130 positioned at the lower side of thereof. The coolant moved to the lower side through the rear flowing path 122″ of coolant is moved again to the tank 130 at the upper rear side through the rear flowing path 122″ of coolant so as to be flowed together. Then, the coolant is moved in a horizontal direction to the tank 130 at the upper front side and moved to the lower side while being branched off through the front flowing path 122′ of coolant and then flowed together in the tank 130 at the lower front side. Sequentially, the coolant is moved again in the horizontal direction and moved to upper side while being branched off through the front flowing path 122′ of coolant and then flowed together in the tank 130 at upper front side. And the coolant is flowed in the outlet manifold 161 through the communicating opening 163 formed at the outlet end-plate 160 and then discharged to the outflow part 162 of the outlet end-plate 160. By the process as described above, the liquidized coolant is evaporated and the evaporated coolant is discharged to an outlet pipe 170 through the outlet manifold 161 and the outlet end-plate 160. At this time, since the coolant is in a vapor phase at the outlet side, the coolant has a high flowing speed.
In the conventional evaporator, when the coolant which is flowed together in the tank 130 positioned at the front side through the communicating opening 163 formed at the outlet end-plate 160 flowed the outlet manifold 161 and discharged to the outflow part 162 of the outlet end-plate 160, the coolant flowed the front side of the outlet manifold 161, i.e., the upstream side of air flow as well as the rear side thereof, i.e., the downstream side of air flow. At this time, the coolant moved to the downstream side, i.e., the rear side of the outlet manifold 161 generates a whirling phenomenon indicated by a blue color in FIG. 4, and thus the flowing speed is lowed and a pressure loss is increased. As described above, at the downstream side of the outlet manifold 161, there is a dead zone which is unnecessary for the flowing of coolant. Therefore, there is a problem that the evaporated coolant having the high flowing speed forms a floating phenomenon like an open cavity due to the dead zone, thereby generating a noise.